Pressurized resistance welding

Figure 10.46 Metallography of pressurized resistance welding (PRW) part after fuel pin irradiation at BOR-60.

M. Seki, K. Hirako, S. Kono, Y. Kihara, T. Kaito, S. Ukai, Pressurized resistance welding technology development in 9Cr-ODS martensitic steels, J. Nucl. Mater. 329—333 (2004) 1534-1538. 

A Russian ammonia pipeline of nearly 2400 km extends from Togliatti on the Volga River to the Port of Odessa on the Black Sea, and a 2200-km, 250-mm dia branch line extends from Godovka in the Ukraine to Panioutino. The pipeline is constmcted of electric-resistance welded steel pipe with 7.9-mm thick walls but uses seamless pipe with 12.7-mm thick walls for river crossings. The pipeline is primed and taped with two layers of polyethylene tape and suppHed with a cathodic protection system for the entire pipeline. Mainline operating pressure is 8.15 MPa (1182 psi) and branch-line operating pressure is 9.7 MPa (1406 psi) (11). 

Abstract. The present work deals with major technical items related to defectoscopy of metallic materials - in particular, welded joints - which can be considered as constitutive for H-storage high pressure tanks such vessels must be corrosion and pressure-resistant, especially in order to avoid any infiltration by light H-atoms and, in general, H-embrittlement and Stress Corrosion Cracking (SCC) phenomena. 

For instance, for a 304 stainless steel welded seam pipe with an outside diameter of 3V2", to find the maximum internal pressure allowed for this pipe, use the pressure formula. Find what is called the stress value for a particular material (in this case 304 stainless steel) which is based on that material and the way it was fabricated - whether it is seamless, continuous welded, electric resistance welded, or electric fusion-arc welded. Most of the materials that you will run into will be ERW (electric resistance welded ) and thus have a seam, or will be seamless with no weld. The same material of a given diameter and thickness will be able to withstand higher internal pressure if it is seamless. 

Establishing the pipe material, the wall thickness, and the condition of the pipe (particularly internal or external corrosion) and the effect of welding on the pressure-resistance strength of the pipe, if welding is to be performed. 

Schouteten et al. (127) described a simple stainless steel DSC sample cell that is sealed by a resistance welding technique. The welded capsule could withstand pressures of over 80 atm. 

Typically resistance welding operation is characterized by both fusion of the base material and a pressure applied between the two parts to be welded. No filler is used for such kind of... 

Resistance welding - where both heat and pressure are applied. 

As compared to carbon steels, a resistance welding of austenitic stainless steels is possible with shorter welding times and lower welding currents than in the case of carbon steels because of their higher electrical resistivity. By comparison, the welding pressure must be higher for stainless steels. 

Rhodium was chosen as construction material for the reactor, which served as active catalyst species at the same time. Rhodium has a high thermal conductivity of 120 W/(m K). Twenty three foils carrying 28 channels each of which was sealed by electron beam and laser welding. The stack of foils formed a honeycomb which was pressure resistant up to 30 bar. The maximum operating temperature of the reactor was 1200°C. The feed was preheated to 300° C and then fed to the reactor. The experiments were carried out between ambient pressure and 25 bar at 0/C ratio 1.0. After ignition of the reaction between 550 and 700°C, 1000°C reaction temperature was then achieved within 1 min, and mainly carbon monoxide and hydrogen were formed. Only 62% conversion of methane but 98% conversion of oxygen was achieved at 1190°C. The performance of the reactor deteriorated when the system pressure was increased. By-product and even soot formation then occurred downstream the reactor. 

In implant resistance welding, an electrically resistive element that is placed at the joint interface is heating by either direct or alternating current [2], The resistive implant may be as simple as a nichrome or stainless steel wire or mesh. More complex implants can be tapes of braided metallic wire with thermoplastic monofilaments or a composite of polymer matrix with electrically conductive particles or fibers. As shown in Fig. 26.26, during implant induction welding, the resistive implant is placed between the two parts. Electric current is then passed for a preset time through the resistance implant while the parts are under pressure. Then the current flow stops and the parts are kept under pressure while the weld cools, and the implant remains at the joint interface. 

Upset resistance welding electrical resistance between two abutting surfaces and additional pressure used to create butt welds on small pipe assemblies, rings and strips. 

Percussion resistance welding rapid discharge of electrical current and then percussion pressure for welding rods or tubes to sheet-metal. 

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